With a processing tank that pools a processing liquid containing a sedimentable component such as an electrodeposition paint, a known method for preventing settling of the sedimentable component involves arranging ejector nozzles side by side at a predetermined pitch on the bottom part of the processing tank in a width direction of the tank, arranging groups of such ejector nozzles side by side in a longitudinal direction of the tank, and having each ejector nozzle eject the processing liquid to fluidize and agitate the processing liquid pooled in the processing tank (for example, refer to Patent Document 1).    Patent Document 1: Japanese Utility Model Laid-Open No. 01-106573